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| Tool Post Grinding (Dec
6, 2001) |
Toolpost grinder? (May
23, 2003) |
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| Tool Post Grinding |
| I am in
the process of completing a fixture that will allow me to mount a
high speed grinder in my turret tool post. My questions are: what is
the "ideal" positioning of the grinding bit/wheel, with respect to
the work piece? Should it be, say, as in the placement of the
parting tool, dead, on center? And, should the work revolve in
counter rotation to that of the grinder? Does it matter? Norman (2344) |
| I would follow what machine tool
builders do. The grinding wheel should be "on center" with the work.
The grinding wheel and work should rotate in opposite directions.
It's really the only way to go. If the centers are different, the
cross feed dial doesn't read correctly. If both run in the same
direction the grinding wheel wants to rotate the part instead of
grinding it. Try to cover as much of the ways, (and almost
everything) to keep it from getting full of grinding "dust" (while
also trying to keep these "covers" from getting caught up in the
grinding process). Don't know if you are doing O.D. or I.D. grinding
or if you will be grinding on the front or back side of the work.
Either way, at the point of contact, the grinding wheel should be
rotating "down" and the work rotating "up". (2347) |
| Your OD grinder
should have its wheel on dead-center. The lathe turns C/W, the
grinder turns C/C. Before you do to much, cover the ways with stiff
paper or some other covering lest you wish to re-grind your lathe in
the process.8-(( If you are grinding a long shaft, pre-set the
tail-stock so the shaft has no taper, in fact place a mark on the
side of the ways showing where your tail-stock was when you were
turning it. Depending on how much taper you can live with, grind a
test bar and set your t/stock to compensate for error. This way you
can be much more confident of the final figure of your work. Once
you have done this ask a question. Do I grind wet or dry? PROS: Wet
grinding will keep the heat-checking down as well as getting 'holes'
in the work. When a work-surface gets warm, it rises to the wheel
and gets ground. Then after it cools, you get a nice hole in the
work. Wet-grinding eliminates this somewhat. CONS: That water has to
go somewhere, like on the bed and head-stock. Carrying with it all
that nice dust. What's to do? Grind with a mist. This is mostly air
with some water in it. You will get some water on the machine but it
is fairly easy to clean up. If you have a compressor, make or by a
siphon unit that has a metering valve. You simply dial in the
density of your mist. Add some red food coloring so you can see the
grit while cleaning up afterwards. Use a wet-vac and oval brush to
do this, NEVER ANY TYPE OF AIR-HOSE!!! Be meticulous about cleaning
up. A roll of paper towels is lots cheaper then a new lathe. OTHER
TIPS: 1.Use an open-grit white wheel #80 around 3-8" in dia. 2.
Dress your wheel after the unit warms up to 'run-temp' USE A DIAMOND
held in the head stock prior to inserting the work. 3.Take light
cuts. You should leave no more then .008 for grinding, adding in
this as a factor prior to rough machining and heat-treating. To much
grinding only wears everything out faster. 4. ID grinding uses the
same basic parameters. You should use water for this, never oil.
That can idea I wrote about the other day will serve as a fast drip
dispenser. Just point the tube so the water gets inside. The lathe
turns opposite the stone. Ron (2349) |
| Toolpost
grinder? |
| What size (model #)
Dumore Grinder will fit my SB 9 inch? Seems they were quite numerous
the last time I walked around my local tool re- sellers shops! Maybe
now is the time (avg. price about $200.00)! This seems like a great
item to have. Tim (11351) |
| Tim, I have an old
DuMore #44 for my 9" Model A. The literature states that it is made
for this size of lathe. Having said that, I had to make a new
Tee-pedestal so the TPG could be mounted low enough on my compound.
I'm not sure if the Tee-pedestal that came with my old unit was the
standard one, or if different ones are available. Let me know if you
need more info or pictures. Paul R. Hvidston (11370) |
| Tim I have a Dumore
#11. I use it on a SB Heavy 10, but it certainly appears it would be
suitable for a slightly smaller lathe such as a SB 9" as well. At
1/5 HP it is I think near the low end of the food chain for Dumore
grinders, but is suitable for the light grinding I need to do from
time to time. As a low end Dumore it may also come with a low end
price. I paid $100 for mine a few years ago, with a case and a bunch
of grinding wheels. It supports both inside and outside grinding
(with a single, fixed spindle), and has 2 step pulleys to support
both small and larger wheels. Frank (11394) |
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